Permanent mold with core pulling device

Abstract

A permanent mold is equipped with a core pulling device covered with a thin sand jacket, that can be peeled off, in order to produce unregular caves in the cast.

We claim: 
     
       1. An apparatus for forming a corbelled cavity in a casting, comprising: a permanent mold shell having a wall with inner and outer surfaces defining an interior mold cavity;   at least one through bore in said wall opening on said outer surface of said wall and into said mold cavity;   a core holding device removably mounted in said bore, said core holding device having a portion extending radially inwardly from said outer surface with transverse cross-sectional dimensions not greater than corresponding transverse cross-sectional dimensions of said bore such that said core holding device is removable from said bore in a generally radially outward direction relative to said mold cavity;   a metal stud coupled to said core holding device and extending into said mold cavity, said stud having transverse cross-sectional dimensions not greater than said transverse cross-sectional dimensions of said core holding device such that said stud is removable through said bore with said core holding device; and   a shaped jacket of molding material surrounding said stud, and extending into and terminating within said mold cavity, and said jacket having portions within said mold cavity of enlarged dimensions spaced from said core holding device;   whereby, said core holding device and said stud can be removed from said mold cavity and wall after solidification of molten casting material about said jacket, but prior to removal of the casting from said mold shell, leaving said jacket in the casting for subsequent removal to provide a corbelled cavity in the casting with interior dimensions greater than entry opening dimensions.   
     
     
       2. An apparatus according to claim 1 wherein said stud is noncircular in cross section. 
     
     
       3. An apparatus according to claim 2 wherein said core holding device includes means for preventing rotation relative to said wall. 
     
     
       4. An apparatus according to claim 2 wherein said stud has longitudinal ribs on its outer surface. 
     
     
       5. An apparatus according to claim 4 wherein said core holding device includes means for preventing rotation relative to said wall. 
     
     
       6. An apparatus according to claim 1 wherein said stud has longitudinal ribs on its outer surface. 
     
     
       7. An apparatus according to claim 6 wherein said core holding device includes means for preventing rotation relative to said wall. 
     
     
       8. An apparatus according to claim 1 wherein said core holding device includes means for preventing rotation relative to said wall. 
     
     
       9. An apparatus according to claim 1 wherein said jacket completely surrounds said stud in said mold cavity. 
     
     
       10. An apparatus according to claim 1 including an adhesive holding said jacket on said stud. 
     
     
       11. An apparatus according to claim 1 wherein said stud is tapered, decreasing in cross section toward the distal end thereof. 
     
     
       12. An apparatus according to claim 11 wherein said stud is formed from a copper-chromium alloy. 
     
     
       13. An apparatus according to claim 12 wherein said core holding device is formed from a copper-chromium alloy. 
     
     
       14. An apparatus according to claim 1 wherein said stud and core holding device are unitarily formed. 
     
     
       15. An apparatus according to claim 14 and further including means for water-cooling said stud. 
     
     
       16. An apparatus according to claim 15 and further including means defining a gas vent pipe extending from said jacket through said core holding device. 
     
     
       17. An apparatus according to claim 1 and further including means for water-cooling said stud. 
     
     
       18. An apparatus according to claim 17 and further including means defining a gas vent pipe extending from said jacket through said core holding device.